1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
|
<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta name="generator" content="Docutils 0.13.1: http://docutils.sourceforge.net/" />
<title>Xapian::QueryParser Syntax</title>
<style type="text/css">
/*
:Author: David Goodger (goodger@python.org)
:Id: $Id: html4css1.css 7952 2016-07-26 18:15:59Z milde $
:Copyright: This stylesheet has been placed in the public domain.
Default cascading style sheet for the HTML output of Docutils.
See http://docutils.sf.net/docs/howto/html-stylesheets.html for how to
customize this style sheet.
*/
/* used to remove borders from tables and images */
.borderless, table.borderless td, table.borderless th {
border: 0 }
table.borderless td, table.borderless th {
/* Override padding for "table.docutils td" with "! important".
The right padding separates the table cells. */
padding: 0 0.5em 0 0 ! important }
.first {
/* Override more specific margin styles with "! important". */
margin-top: 0 ! important }
.last, .with-subtitle {
margin-bottom: 0 ! important }
.hidden {
display: none }
.subscript {
vertical-align: sub;
font-size: smaller }
.superscript {
vertical-align: super;
font-size: smaller }
a.toc-backref {
text-decoration: none ;
color: black }
blockquote.epigraph {
margin: 2em 5em ; }
dl.docutils dd {
margin-bottom: 0.5em }
object[type="image/svg+xml"], object[type="application/x-shockwave-flash"] {
overflow: hidden;
}
/* Uncomment (and remove this text!) to get bold-faced definition list terms
dl.docutils dt {
font-weight: bold }
*/
div.abstract {
margin: 2em 5em }
div.abstract p.topic-title {
font-weight: bold ;
text-align: center }
div.admonition, div.attention, div.caution, div.danger, div.error,
div.hint, div.important, div.note, div.tip, div.warning {
margin: 2em ;
border: medium outset ;
padding: 1em }
div.admonition p.admonition-title, div.hint p.admonition-title,
div.important p.admonition-title, div.note p.admonition-title,
div.tip p.admonition-title {
font-weight: bold ;
font-family: sans-serif }
div.attention p.admonition-title, div.caution p.admonition-title,
div.danger p.admonition-title, div.error p.admonition-title,
div.warning p.admonition-title, .code .error {
color: red ;
font-weight: bold ;
font-family: sans-serif }
/* Uncomment (and remove this text!) to get reduced vertical space in
compound paragraphs.
div.compound .compound-first, div.compound .compound-middle {
margin-bottom: 0.5em }
div.compound .compound-last, div.compound .compound-middle {
margin-top: 0.5em }
*/
div.dedication {
margin: 2em 5em ;
text-align: center ;
font-style: italic }
div.dedication p.topic-title {
font-weight: bold ;
font-style: normal }
div.figure {
margin-left: 2em ;
margin-right: 2em }
div.footer, div.header {
clear: both;
font-size: smaller }
div.line-block {
display: block ;
margin-top: 1em ;
margin-bottom: 1em }
div.line-block div.line-block {
margin-top: 0 ;
margin-bottom: 0 ;
margin-left: 1.5em }
div.sidebar {
margin: 0 0 0.5em 1em ;
border: medium outset ;
padding: 1em ;
background-color: #ffffee ;
width: 40% ;
float: right ;
clear: right }
div.sidebar p.rubric {
font-family: sans-serif ;
font-size: medium }
div.system-messages {
margin: 5em }
div.system-messages h1 {
color: red }
div.system-message {
border: medium outset ;
padding: 1em }
div.system-message p.system-message-title {
color: red ;
font-weight: bold }
div.topic {
margin: 2em }
h1.section-subtitle, h2.section-subtitle, h3.section-subtitle,
h4.section-subtitle, h5.section-subtitle, h6.section-subtitle {
margin-top: 0.4em }
h1.title {
text-align: center }
h2.subtitle {
text-align: center }
hr.docutils {
width: 75% }
img.align-left, .figure.align-left, object.align-left, table.align-left {
clear: left ;
float: left ;
margin-right: 1em }
img.align-right, .figure.align-right, object.align-right, table.align-right {
clear: right ;
float: right ;
margin-left: 1em }
img.align-center, .figure.align-center, object.align-center {
display: block;
margin-left: auto;
margin-right: auto;
}
table.align-center {
margin-left: auto;
margin-right: auto;
}
.align-left {
text-align: left }
.align-center {
clear: both ;
text-align: center }
.align-right {
text-align: right }
/* reset inner alignment in figures */
div.align-right {
text-align: inherit }
/* div.align-center * { */
/* text-align: left } */
.align-top {
vertical-align: top }
.align-middle {
vertical-align: middle }
.align-bottom {
vertical-align: bottom }
ol.simple, ul.simple {
margin-bottom: 1em }
ol.arabic {
list-style: decimal }
ol.loweralpha {
list-style: lower-alpha }
ol.upperalpha {
list-style: upper-alpha }
ol.lowerroman {
list-style: lower-roman }
ol.upperroman {
list-style: upper-roman }
p.attribution {
text-align: right ;
margin-left: 50% }
p.caption {
font-style: italic }
p.credits {
font-style: italic ;
font-size: smaller }
p.label {
white-space: nowrap }
p.rubric {
font-weight: bold ;
font-size: larger ;
color: maroon ;
text-align: center }
p.sidebar-title {
font-family: sans-serif ;
font-weight: bold ;
font-size: larger }
p.sidebar-subtitle {
font-family: sans-serif ;
font-weight: bold }
p.topic-title {
font-weight: bold }
pre.address {
margin-bottom: 0 ;
margin-top: 0 ;
font: inherit }
pre.literal-block, pre.doctest-block, pre.math, pre.code {
margin-left: 2em ;
margin-right: 2em }
pre.code .ln { color: grey; } /* line numbers */
pre.code, code { background-color: #eeeeee }
pre.code .comment, code .comment { color: #5C6576 }
pre.code .keyword, code .keyword { color: #3B0D06; font-weight: bold }
pre.code .literal.string, code .literal.string { color: #0C5404 }
pre.code .name.builtin, code .name.builtin { color: #352B84 }
pre.code .deleted, code .deleted { background-color: #DEB0A1}
pre.code .inserted, code .inserted { background-color: #A3D289}
span.classifier {
font-family: sans-serif ;
font-style: oblique }
span.classifier-delimiter {
font-family: sans-serif ;
font-weight: bold }
span.interpreted {
font-family: sans-serif }
span.option {
white-space: nowrap }
span.pre {
white-space: pre }
span.problematic {
color: red }
span.section-subtitle {
/* font-size relative to parent (h1..h6 element) */
font-size: 80% }
table.citation {
border-left: solid 1px gray;
margin-left: 1px }
table.docinfo {
margin: 2em 4em }
table.docutils {
margin-top: 0.5em ;
margin-bottom: 0.5em }
table.footnote {
border-left: solid 1px black;
margin-left: 1px }
table.docutils td, table.docutils th,
table.docinfo td, table.docinfo th {
padding-left: 0.5em ;
padding-right: 0.5em ;
vertical-align: top }
table.docutils th.field-name, table.docinfo th.docinfo-name {
font-weight: bold ;
text-align: left ;
white-space: nowrap ;
padding-left: 0 }
/* "booktabs" style (no vertical lines) */
table.docutils.booktabs {
border: 0px;
border-top: 2px solid;
border-bottom: 2px solid;
border-collapse: collapse;
}
table.docutils.booktabs * {
border: 0px;
}
table.docutils.booktabs th {
border-bottom: thin solid;
text-align: left;
}
h1 tt.docutils, h2 tt.docutils, h3 tt.docutils,
h4 tt.docutils, h5 tt.docutils, h6 tt.docutils {
font-size: 100% }
ul.auto-toc {
list-style-type: none }
</style>
</head>
<body>
<div class="document" id="xapian-queryparser-syntax">
<h1 class="title">Xapian::QueryParser Syntax</h1>
<p>This document describes the query syntax supported by the
Xapian::QueryParser class. The syntax is designed to be similar to other
web based search engines, so that users familiar with them don't have to
learn a whole new syntax.</p>
<div class="section" id="operators">
<h1>Operators</h1>
<div class="section" id="and">
<h2>AND</h2>
<p><em>expression</em> AND <em>expression</em> matches documents which are matched by
both of the subexpressions.</p>
</div>
<div class="section" id="or">
<h2>OR</h2>
<p><em>expression</em> OR <em>expression</em> matches documents which are matched by
either of the subexpressions.</p>
</div>
<div class="section" id="not">
<h2>NOT</h2>
<p><em>expression</em> NOT <em>expression</em> matches documents which are matched by
only the first subexpression. This can also be written as <em>expression</em>
AND NOT <em>expression</em>. If <tt class="docutils literal">FLAG_PURE_NOT</tt> is enabled, then</p>
<p>NOT <em>expression</em> will match documents which don't match the
subexpression.</p>
</div>
<div class="section" id="xor">
<h2>XOR</h2>
<p><em>expression</em> XOR <em>expression</em> matches documents which are matched by one
or other of the subexpressions, but not both. XOR is probably a bit
esoteric.</p>
</div>
<div class="section" id="bracketed-expressions">
<h2>Bracketed expressions</h2>
<p>You can control the precedence of the boolean operators using brackets.
In the query <tt class="docutils literal">one OR two AND three</tt> the AND takes precedence, so this
is the same as <tt class="docutils literal">one OR (two AND three)</tt>. You can override the
precedence using <tt class="docutils literal">(one OR two) AND three</tt>.</p>
<p>The default precedence from highest to lowest is:</p>
<ul class="simple">
<li>+, - (equal)</li>
<li>AND, NOT (equal)</li>
<li>XOR</li>
<li>OR</li>
</ul>
</div>
<div class="section" id="id1">
<h2>'+' and '-'</h2>
<p>A group of terms with some marked with + and - will match documents
containing all of the + terms, but none of the - terms. Terms not marked
with + or - contribute towards the document rankings. You can also use +
and - on phrases and on bracketed expressions.</p>
</div>
<div class="section" id="near">
<h2>NEAR</h2>
<p><tt class="docutils literal">one NEAR two NEAR three</tt> matches documents containing those words
within 10 words of each other. You can set the threshold to <em>n</em> by using
<tt class="docutils literal">NEAR/n</tt> like so: <tt class="docutils literal">one NEAR/6 two</tt>.</p>
</div>
<div class="section" id="adj">
<h2>ADJ</h2>
<p><tt class="docutils literal">ADJ</tt> is like <tt class="docutils literal">NEAR</tt> but only matches if the words appear in the
same order as in the query. So <tt class="docutils literal">one ADJ two ADJ three</tt> matches
documents containing those three words in that order and within 10 words
of each other. You can set the threshold to <em>n</em> by using <tt class="docutils literal">ADJ/n</tt> like
so: <tt class="docutils literal">one ADJ/6 two</tt>.</p>
</div>
<div class="section" id="phrase-searches">
<h2>Phrase searches</h2>
<p>A phrase surrounded with double quotes ("") matches documents containing
that exact phrase. Hyphenated words are also treated as phrases, as are
cases such as filenames and email addresses (e.g. <tt class="docutils literal">/etc/passwd</tt> or
<tt class="docutils literal">president@whitehouse.gov</tt>).</p>
</div>
<div class="section" id="searching-within-a-probabilistic-field">
<h2>Searching within a probabilistic field</h2>
<p>If the database has been indexed with prefixes on probabilistic terms
from certain fields, you can set up a prefix map so that the user can
search within those fields. For example <tt class="docutils literal">author:dickens title:shop</tt>
might find documents by dickens with shop in the title. You can also
specify a prefix on a quoted phrase (e.g. <tt class="docutils literal"><span class="pre">author:"charles</span> dickens"</tt>)
or on a bracketed subexpression (e.g. <tt class="docutils literal"><span class="pre">title:(mice</span> men)</tt>).</p>
</div>
<div class="section" id="searching-for-proper-names">
<h2>Searching for proper names</h2>
<p>If a query term is entered with a capitalised first letter, then it will
be searched for unstemmed.</p>
</div>
<div class="section" id="range-searches">
<h2>Range searches</h2>
<p>The QueryParser <a class="reference external" href="valueranges.html">can be configured to support
range-searching</a> using document values.</p>
<p>The syntax for a range search is <tt class="docutils literal"><span class="pre">start..end</span></tt> - for example,
<tt class="docutils literal"><span class="pre">01/03/2007..04/04/2007</span></tt>, <tt class="docutils literal"><span class="pre">$10..100</span></tt>, <tt class="docutils literal"><span class="pre">5..10kg</span></tt>.</p>
<p>Open-ended ranges are also supported - an empty start or end is
interpreted as no limit, for example: <tt class="docutils literal"><span class="pre">..2010-06-17</span></tt>, <tt class="docutils literal">$10..</tt>,
<tt class="docutils literal"><span class="pre">$..100</span></tt>, <tt class="docutils literal">..5kg</tt>.</p>
</div>
<div class="section" id="synonyms">
<h2>Synonyms</h2>
<p>The QueryParser can be configured to support synonyms, which can either
be used when explicitly specified (using the syntax <tt class="docutils literal">~term</tt>) or
implicitly (synonyms will be used for all terms or groups of terms for
which they have been specified).</p>
</div>
<div class="section" id="wildcards">
<h2>Wildcards</h2>
<p>The QueryParser supports using a trailing '*' wildcard, which matches
any number of trailing characters, so <tt class="docutils literal">wildc*</tt> would match wildcard,
wildcarded, wildcards, wildcat, wildcats, etc. This feature is disabled
by default - pass <tt class="docutils literal"><span class="pre">Xapian::QueryParser::FLAG_WILDCARD</span></tt> in the flags
argument of <tt class="docutils literal"><span class="pre">Xapian::QueryParser::parse_query(query_string,</span> flags)</tt> to
enable it, and tell the QueryParser which database to expand wildcards
from using the <tt class="docutils literal"><span class="pre">QueryParser::set_database(database)</span></tt> method.</p>
<p>You can limit the number of terms a wildcard will expand to by
calling <tt class="docutils literal"><span class="pre">Xapian::QueryParser::set_max_wildcard_expansion()</span></tt>. If a
wildcard expands to more terms than that number, an exception will be
thrown. The exception may be thrown by the QueryParser, or later when
Enquire handles the query. The default is not to limit the expansion.</p>
</div>
<div class="section" id="partially-entered-query-matching">
<h2>Partially entered query matching</h2>
<p>The QueryParser also supports performing a search with a query which has
only been partially entered. This is intended for use with "incremental
search" systems, which don't wait for the user to finish typing their
search before displaying an initial set of results. For example, in such
a system a user would enter a search, and the system would display a new
set of results after each letter, or whenever the user pauses for a
short period of time (or some other similar strategy).</p>
<p>The problem with this kind of search is that the last word in a
partially entered query often has no semantic relation to the completed
word. For example, a search for "dynamic cat" would return a quite
different set of results to a search for "dynamic categorisation". This
results in the set of results displayed flicking rapidly as each new
character is entered. A much smoother result can be obtained if the
final word is treated as having an implicit terminating wildcard, so
that it matches all words starting with the entered characters - thus,
as each letter is entered, the set of results displayed narrows down to
the desired subject.</p>
<p>A similar effect could be obtained simply by enabling the wildcard
matching option, and appending a "*" character to each query string.
However, this would be confused by searches which ended with punctuation
or other characters.</p>
<p>This feature is disabled by default - pass
<tt class="docutils literal"><span class="pre">Xapian::QueryParser::FLAG_PARTIAL</span></tt> flag in the flags argument of
<tt class="docutils literal"><span class="pre">Xapian::QueryParser::parse_query(query_string,</span> flags)</tt> to enable it,
and tell the QueryParser which database to expand wildcards from using
the <tt class="docutils literal"><span class="pre">QueryParser::set_database(database)</span></tt> method.</p>
</div>
</div>
</div>
</body>
</html>
|
